Extreme style copper core with 1/2" tubes on 5/16" centers. Offers 40% more heat transfer points. The most efficient core on the market when combined with increased air-flow and our Tripleflow option (note: In almost all cases, we will not sell the Optima core without the Tripleflow option. Our Tripleflow option requires that inlet and outlet be on opposite sides and must use auxillary tranny cooler for automatic transmission vehicles). LEARN MORE